1. Field of the Invention
The present invention relates to a power line communication in an image forming apparatus.
2. Description of the Related Art
In conventional image forming apparatuses, a method of greatly reducing the number of signal lines used for communication and control signal lines by performing data transfer by way of serial communication is implemented in a unit (circuit board) that does not require high data transfer speed. However, a large number of signal lines are provided between the circuit boards in the image forming apparatus as a whole. Further, many power lines are provided for power supply to the circuit boards in addition to the communication and control signal lines. The communication and control signal lines and the power lines occupy a large part of a space in the image forming apparatus.
U.S. Patent Application Publication No. 2006/0077046 discusses that, to further reduce the number of communication and signal lines, the number of communication and control signal line bundles is reduced by using a power line as a signal transmission path and performing the communication between a plurality of circuit boards connected to the power line and a control module.
In the case of performing signal transmission by using a power line, it is desirable that a transmission path is electrically stable for enabling stable communication. However, in image forming apparatuses, a current supplied from a direct current power source is sometimes changed to a large degree depending on an operational status of a load during an image forming operation. Particularly, a current power source assigned to a driving unit such as a motor and an actuator is greatly fluctuated depending on an operation state. Since impedance in the transmission path is also greatly fluctuated in such a power line, it is sometimes difficult to perform the stable communication depending on the operation status of the image forming apparatus.